How to inspect a second-hand excavator before you buy

Before the yard visit

The best inspection starts a week before you drive. Ask the dealer for three things in writing: the full service history (even if partial), a current hour-meter photograph with a visible date stamp, and the Datenblatt PDF generated from the dealer's system. Compare the Datenblatt serial number against the chassis plate — a mismatch is a conversation.

Walk-around (first 10 minutes)

1. Chassis plate — serial, year, EU conformity CE stamp present, not re-stamped.
2. Hour meter reading — photograph it. Compare to the service book.
3. Hydraulic fittings — any fresh paint around fittings = recent repair; ask why.
4. Oil leaks — floor under machine. Drip spots at parked position = active leak.
5. Boom + arm wear — pins and bushings; horizontal play test with bucket on ground.
6. Tracks or tyres — pad height / tread depth. Replacement sets are 5–12k€ depending on size.
7. Cab glass + door seals — cheap to notice, expensive to replace.

Engine (next 15 minutes)

Cold start matters. Ask the operator to leave the key off until you arrive. Then:

• Clear smoke on cold start → piston rings OK.
• White smoke that persists → coolant in the combustion chamber (head gasket, bad).
• Blue smoke under load → oil consumption; budget for a rebuild sooner.
• Black smoke after warm-up at idle → injector trouble; manageable, but factor it.

After 10 minutes idling, open the oil cap. Mayonnaise-coloured residue inside the cap = coolant getting into the oil. Walk away unless the price reflects a top-end rebuild.

Hydraulics test

With the machine warm, run the following cycles and watch pressure gauges + listen:

1. Full boom lift to maximum — should be smooth, no "steps."
2. Full arm curl in + out — no jerking at mid-stroke.
3. Bucket curl in / dump — fast movement at the end of stroke, no drift when held.
4. Swing full 360° both directions — no squeaks, no overshoot at stop.
5. Track travel both directions — no pulling to one side on level ground.

Drift test: lift the boom horizontal with bucket loaded. Shut down the engine. Walk around for 2 minutes. If the boom has visibly dropped, cylinder seals are tired. Not a dealbreaker, but negotiate accordingly.

Undercarriage (the money zone)

Undercarriage is 20–30% of the machine's lifetime cost. Measure three things on tracked machines:

• Pad height remaining vs. new (typically 50mm new, replace at 15mm).
• Pin and bushing wear — place a bar under the track, lift — more than 10mm vertical play = replace soon.
• Sprocket teeth — sharp = worn, rounded profile = healthy.

Paperwork review (final 20 minutes)

Back inside. Ask for:

• Service book — matched hour-meter stamps per service interval.
• Oil analysis report (if available) — flags coolant leaks, bearing wear, fuel dilution.
• Previous owner records — ideally a single-owner machine with fleet maintenance.
• Attachment compatibility list — buckets, hammers, quick-couplers.

A machine with no paperwork is not necessarily bad — but it is a 10–15% discount from comparable-but-documented machines.

Price triangulation

We benchmark against three sources: MachineryTrader EU, Trucksnl, and our own closed-sale history over 18 months. If the asked price is more than 8% above all three, there has to be a reason — hours, condition, rare attachments, or a very recent major component. Ask for the reason and verify it.

Red flags that end the inspection

• Visible frame weld repairs on the main boom or stick.
• Non-matching chassis serial vs. engine serial without documented engine swap.
• Coolant in oil, oil in coolant.
• Dealer refuses to let you power-cycle the machine from cold.
• Service book pages missing or looks newly reprinted.

Printable checklist

Download the full 42-point PDF checklist we use on every machine that enters our Altrip yard. It's the same document our mechanic signs off before a machine goes on the public catalog.

A note on scope

This guide covers 15–40t excavators. For wheel loaders, dumpers, and compact machines, the checklist overlaps 70% — the key difference is attachment interfaces and transmission tests. We'll publish those as separate guides.